Trench-conformable geothermal heat exchange reservoirs and related methods and systems

ABSTRACT

The disclosure describes trench-confirmable geothermal reservoirs that can snugly abut trench walls (that may be of virgin, compacted earth) for facilitating heat exchange and flow liquid from one lower end to an opposing top end, and vice versa, depending on desired heat exchange. The direction can be reversed for summer and winter heat/cooling configurations. A series of the reservoirs may be used for appropriate heat transfer. The water volume of the reservoirs is relatively large and slow moving for good earth heat conduction.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/899,559, filed Feb. 20, 2018, which is a continuation of U.S. patentapplication Ser. No. 15/010,268, filed Jan. 29, 2016, now U.S. Pat. No.9,933,172, issued Apr. 3, 2018, which is a continuation of U.S. patentapplication Ser. No. 13/788,495, filed Mar. 7, 2013, now U.S. Pat. No.9,284,952, issued Mar. 15, 2016, which claims the benefit of andpriority to U.S. Provisional Application Ser. No. 61/675,040, filed Jul.24, 2012, the contents of which are hereby incorporated by reference asif recited in full herein.

FIELD OF THE INVENTION

This invention relates to geothermal heat exchangers.

BACKGROUND

Geothermal heat exchangers are well known and include closed geothermalground horizontal or vertical loops. In a closed loop system, a loop ofpiping is buried underground and filled with liquid such as water orantifreeze that continuously circulates through the system.

Horizontal geothermal ground loops typically use several hundred feet offour to six feet deep trenches. Piping is laid in the trench andbackfilled. A typical horizontal ground loop will employ several hundredfeet of pipe for each ton of heating and cooling. The horizontal pipescan be straight pipes but are more typically coiled type, the so-called“slinky coil” configuration with overlapped loops of piping arrangedhorizontally along the bottom of a wide trench. See, e.g., U.S.2011/0011558, the contents of which are hereby incorporated by referenceas if recited in full herein.

Vertical or deep bore geothermal ground loops are typically placed intothe ground at much deeper depths than the trench based systems, such asbetween 150-300 feet. In vertical geothermal ground loops, a drillingrig is used to drill 150 to 300 foot deep holes in which hairpin-shapedloops of pipe are dropped, then grouted. A typical vertical ground loopcan also require several hundred feet of pipe per ton of heating andcooling. Drilling costs are more expensive than trenching excavationcosts.

Despite the foregoing, there remains a need for economic alternativegeothermal heat exchangers.

SUMMARY OF EMBODIMENTS OF THE INVENTION

Embodiments of the invention are directed to trench conformablegeothermal heat exchange reservoirs, related methods and systems.

Some embodiments are directed to geothermal heat exchangers for groundtrenches. The geothermal heat exchangers include a substantiallyrectangular flexible or semi-flexible reservoir body having width,height, and length dimensions. The reservoir body has at least one inletport on an upper end portion and at least one exit port on an opposinglower end portion.

The rectangular body can have a width dimension that is between about4-6 inches, and wherein the length dimension is at least two timesgreater than the height dimension.

The heat exchanger can include a length of pipe or conduit that extendsa distance inward into the reservoir body from the inlet and exit ports.

The reservoir body can be configured to expand from a pre-installationshape to a liquid-filled post installation shape and retain that shapeduring operation.

The inlet and exit ports can include pipe or conduit fittings thatengage pipe or conduit in a geothermal loop that is adapted to be influid communication with a water source heat pump or water-cooledcondenser.

The heat exchangers can include at least one support member that isattached to the reservoir body to define an installation shape.

The reservoir body can be sized and configured to reside in a horizontaltrench at a depth below ground surface of between 2-6 feet.

The reservoir body can have a thin, water-impermeable material definingprimary surfaces of a front and rear wall.

The width can be between about 4-6 inches, the height is between about2-6 feet, and the length is between about 10-100 feet.

The width can be between about 4-6 inches, the height can be betweenabout 2-4 feet, and the length can be between about 20-30 feet.

The heat exchanger can also include a plurality of spaced apart internalpartitions alternating to define upper and lower reduced open flowspaces along the length dimension of the reservoir.

The heat exchanger can include a jig with an upper rigid rectangularframe with downwardly extending sidewalls enclosing an upper portion ofthe reservoir body that is releasably attached to an upper surface ofthe reservoir body to facilitate installation and proper filling/shapecontrol.

Other embodiments are directed to geothermal closed loop heat exchangesystems. The systems include at least one flexible or semi-flexiblegeothermal heat exchange reservoir having at least one inlet port and atleast one exit port residing in a horizontal trench a distance belowground surface. The heat exchange reservoir has front and rear primarywalls with an expanded shape that snugly contacts and conforms to ashape of adjacent trench walls. The systems also include a heat pump orwater condenser and a closed loop flow path having a flow directionconnecting the inlet port and the exit port of the reservoir to the heatpump or water condenser to define a closed loop geothermal heat exchangesystem.

The at least one reservoir can be substantially rectangular, with awidth dimension being between 1-12 inches, and wherein the inlet portand exit ports reside on opposing end portions of the reservoir, one atan upper portion and the other at a lower portion.

The at least one reservoir can be a plurality of geothermal heatexchange reservoirs in fluid communication. The reservoirs have upperand lower fluid ports on opposing end portions thereof and (i) forwinter and/or cold weather, water serially flows in the flow path into arespective lower port of a first reservoir, then out of correspondingupper port, then into the lower port on a next reservoir and out of acorresponding upper port and (ii) for summer and/or warm weather, waterserially flows in the flow path into a respective upper port of thefirst reservoir, then out of the lower port, then into the upper port ofthe next reservoir and out of the corresponding upper port.

The at least one reservoir has a substantially rectangular body with awidth dimension that is between about 4-6 inches, and a length dimensionthat is between about 10-100 feet.

The reservoir body can be configured to expand from a pre-installationshape to a liquid-filled post installation shape and retain that shapeduring operation.

The reservoir body can reside inside thin, flexible external cover.

The inlet and exit ports can include pipe or conduit that extends adistance into the reservoir body to facilitate cross flow. The reservoirbody can have at least one support member that is attached to thereservoir body to define an installation shape.

The reservoir body can be substantially rectangular with a width, lengthand height and is sized and configured to reside in a horizontal trenchat a depth below ground surface of between 2-6 feet. The reservoir canhave a body with a thin, water-impermeable material defining primarysurfaces of a front and rear wall. The width can be between about 4-6inches, the height can be between about 2-4 feet, and the length can bebetween about 20-30 feet.

Still other embodiments are directed to methods of installing ageothermal heat transfer system. The methods include: (a) placing aflexible or semi-flexible geothermal heat exchange reservoir with atleast one inlet port and at least one spaced apart outlet port in ahorizontal trench having a floor and upwardly extending trench walls;and (b) filling the heat exchange reservoir with liquid causing thereservoir to expand to snugly contact and conform to the trench walls.

The reservoir can be substantially rectangular and can have a lengththat is between about 10-100 feet and a width between about 2-4 inches.

The method can include placing a second flexible or semi-flexiblegeothermal heat exchange reservoir with at least one inlet port and atleast one spaced apart outlet port in a different horizontal trenchhaving a floor and upwardly extending trench walls, filling the secondheat exchange reservoir with liquid causing the reservoir to expand tosnugly contact and conform to the trench walls, and connecting a closedloop flow path from the reservoirs to a heat pump or water cooledcondenser.

The reservoir can reside inside a flexible outer cover and the methodcan further include expanding the cover outward as the reservoir expandsin response to filling the reservoir.

The reservoirs can have upper and lower fluid ports on opposing endportions thereof, and flow in the closed loop flow path can be in afirst direction in cold weather and in an opposing direction in warmweather such that (i) for winter and/or cold weather, water seriallyflows in the flow path into a respective lower port of a firstreservoir, then out of corresponding upper port, then into the lowerport on a next reservoir and out of a corresponding upper port and (ii)for summer and/or warm weather, water serially flows in the flow pathinto a respective upper port of the first reservoir, then out of thelower port, then into the upper port of the next reservoir and out ofthe corresponding upper port.

The methods can include releasably attaching a jig comprising an upperrigid rectangular frame with downwardly extending sidewalls to an upperportion of the reservoir body so that the upper portion of the reservoirbody is enclosed in the jig before the filling step, then removing thejig from the reservoir body after the filling step.

Still other embodiments are directed to methods of geothermal heattransfer. The methods include flowing water from a pump associated witha heat exchanger or water-cooled condenser in a closed loop a firstdirection during summer and an opposing direction during winter so thatthe water flows through at least one substantially rectangular flexibleor semi-flexible reservoir with a width dimension that is between about1-12 inches, and a length dimension that is between about 10-100 feet,wherein the reservoir resides in a horizontal trench a distance belowground surface with primary rear and front walls that snugly contact andconform to a trench wall shape thereat.

It is noted that aspects of the invention described with respect to oneembodiment, may be incorporated in a different embodiment although notspecifically described relative thereto. That is, all embodiments and/orfeatures of any embodiment can be combined in any way and/orcombination. Applicant reserves the right to change any originally filedclaim or file any new claim accordingly, including the right to be ableto amend any originally filed claim to depend from and/or incorporateany feature of any other claim although not originally claimed in thatmanner. These and other objects and/or aspects of the present inventionare explained in detail in the specification set forth below.

The foregoing and other objects and aspects of the present invention areexplained in detail in the specification set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a geothermal heat transferreservoir according to embodiments of the present invention.

FIG. 2A is a side perspective view of an example of a geothermal heattransfer reservoir having a pre-installation configuration according tosome embodiments of the present invention.

FIG. 2B is a side perspective view of the device shown in FIG. 2A,expanded during or after installation according to embodiments of thepresent invention.

FIG. 2C is a side perspective view of another embodiment of a geothermalreservoir according to embodiments of the present invention.

FIG. 3 is a partial side perspective view of a geothermal heat transferreservoir in operative position and configuration in a horizontal trenchaccording to embodiments of the present invention.

FIG. 4 is a top perspective view of a geothermal heat transfer systemusing at least one flexible or semi-flexible reservoir according toembodiments of the present invention.

FIG. 5 is a front schematic view of a geothermal reservoir illustratingsummer flow direction according to embodiments of the present invention.

FIG. 6A is a front schematic view of the geothermal reservoir shown inFIG. 5 illustrating winter flow direction and an optional external braceor support member according to embodiments of the present invention.

FIG. 6B is a left end view of the device shown in FIG. 6A.

FIG. 6C is a right end view of the device shown in FIG. 6A illustratingan optional right end support member or brace (omitted from FIG. 6A).

FIGS. 7A and 7B are side perspective views of the geothermal reservoirwith other examples of external support members according to embodimentsof the present invention.

FIG. 7C is a side perspective view of a geothermal reservoir with yetanother example of external support members according to embodiments ofthe present invention.

FIG. 7D is an enlarged partial end perspective view of the embodimentshown in FIG. 7C.

FIG. 8 is a side perspective view of an example of a multiple-reservoirsystem with flow direction illustrated for winter flow according toembodiments of the present invention.

FIG. 9A is an end view of another multiple-reservoir system(illustrating winter flow direction) according to embodiments of thepresent invention.

FIG. 9B is a top view of the system shown in FIG. 9A (again illustratingthe winter flow direction).

FIG. 10A is a side schematic view of a geothermal reservoir havinginternal partitions according to embodiments of the present invention.

FIG. 10B is a section view taken along line 10B-10B in FIG. 10Aaccording to embodiments of the present invention.

FIG. 11A is an end view of another embodiment of a geothermal reservoiraccording to embodiments of the present invention.

FIG. 11B is an end view of another embodiment of a geothermal reservoiraccording to embodiments of the present invention.

FIGS. 12A-12C are schematic section sequential views of filling aflexible reservoir held inside a flexible outer cover according toembodiments of the present invention.

FIG. 13 is an end perspective view of a reservoir in a flexible outercover according to embodiments of the present invention.

FIG. 14 is a end section view of yet another embodiment of the inventionillustrating a fluid cavity between the cover and reservoir according tosome embodiments of the present invention.

FIG. 15 is a front view of a jig suitable for installing a reservoirinto a trench according to embodiments of the present invention.

FIG. 16 is a front end perspective view of the jig shown in FIG. 15attached to a reservoir body according to embodiments of the presentinvention.

FIG. 17 is an end view of the jig shown in FIG. 15 attached to areservoir (unfilled) in a trench according to embodiments of the presentinvention.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention will now be described more fully hereinafter withreference to the accompanying figures, in which embodiments of theinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Like numbers refer to like elementsthroughout. In the figures, certain layers, components or features maybe exaggerated for clarity, and broken lines illustrate optionalfeatures or operations unless specified otherwise. In addition, thesequence of operations (or steps) is not limited to the order presentedin the figures and/or claims unless specifically indicated otherwise. Inthe drawings, the thickness of lines, layers, features, componentsand/or regions may be exaggerated for clarity and broken linesillustrate optional features or operations, unless specified otherwise.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes,” and/or “including” when used in thisspecification, specify the presence of stated features, regions, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, regions, steps,operations, elements, components, and/or groups thereof. As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Spatially relative terms, such as “under”, “below”, “lower”, “over”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if a device in thefigures is inverted, elements described as “under” or “beneath” otherelements or features would then be oriented “over” the other elements orfeatures. Thus, the exemplary term “under” can encompass both anorientation of over and under. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Similarly, the terms“upwardly”, “downwardly”, “vertical”, “horizontal” and the like are usedherein for the purpose of relative explanation only unless specificallyindicated otherwise.

The term “about” means that the recited parameter can vary from therecited number, typically by +/− 20%.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the specification andrelevant art and should not be interpreted in an idealized or overlyformal sense unless expressly so defined herein. Well-known functions orconstructions may not be described in detail for brevity and/or clarity.

It will be understood that although the terms “first” and “second” areused herein to describe various regions, layers and/or sections, theseregions, layers and/or sections should not be limited by these terms.These terms are only used to distinguish one region, layer or sectionfrom another region, layer or section. Thus, a first region, layer orsection discussed below could be termed a second region, layer orsection, and similarly, a second without departing from the teachings ofthe present invention.

The terms “virgin compacted soil” or “virgin compacted earth” refer tonatural earth content that is compacted to form a trench withoutrequiring special land fill or added earth or soil content to allow arespective reservoir to have good heat transfer with the virgincompacted earth.

Referring now to the figures, FIG. 1 illustrates a geothermal liquidreservoir 10 that is sized and configured to reside in a substantiallyhorizontal ground trench 20 (FIG. 3) and can be used in lieu of or withconventional geothermal heat exchangers, including all pipe type heatexchangers, vertical, horizontal, coiled or pond.

In some embodiments, as shown by way of example only in FIGS. 2A and 2B,the reservoir body 10 body with ends 10 e, a bottom 10 b, top 10 t andprimary sidewalls 10 f, 10 r. The body can change in external shape froma pre-installation configuration 10 i (FIG. 2A) to a post-installation(and liquid-filled) configuration 10 p (FIG. 2B), e.g., it can expandoutward a sufficient distance to conform to a shape of the adjacenttrench wall 20 w (FIG. 3), so as to substantially retain the rectangularshape and retain this shape during operation, once filled. The post-fillshape can have, for example, sides 10 r, 10 f, more typically ends 10 e,that may be bowed outward to snugly contact adjacent (virgin, compacted)soil immediately upon liquid fill without requiring additionalcompaction or special fill at installation in a manner that can allowfor good heat transfer with earth. The flexible or semi-flexiblereservoir 10 can also be described as a bladder.

The reservoir 10 has a body 10 b can conformably contact a shape of theearth trench walls 20 w during fill with the water/liquid, which canprovide for maximum geothermal heat transfer (to the earth). Thereservoir 10 can be provided with fittings 11 c, 13 c pre-attachedand/or with partial lengths of pipe 30, or these components may beattached at a field use site. FIG. 2C illustrates an end penetrationentry/exit of the pipe 30 at ports 11, 13 while FIGS. 2A and 2Billustrate top and bottom entry/exit at the respective ports 11, 13. Theports 11, 13 are in upper and lower quadrants or corners “upper andlower end portions” of the reservoir, including on either the top and/orbottom walls 10 t, 10 b, the front or rear walls 10 f, 10 r and/or theend walls 10 e so that at least one port 11 is on an upper end portionand at least one exit port 13 is on an opposing lower end portion.

In some embodiments, it may be possible to inflate or partially inflatethe reservoir 10 with gas for ease in installation to help providedesired structure for positioning. End caps can be used to cover theports 11, 13. Once in place, the gas can be released.

As shown in FIG. 3, the reservoir 10 has a body 10 body that isconfigured to be flexible or semi-flexible so as to be able to expand anamount sufficient to conform to the trench shape so that each outerprimary wall 10 f, 10 r snugly abuts against an adjacent upwardlyextending (of virgin, compacted earth) trench wall 20 w, in use, whenfilled or partially filled with liquid, such as water. The bottom of thereservoir 10 b can also expand to contact the adjacent soil. No specialback fill or packing is required at installation. The bottom of thereservoir 10 b can reside on the trench floor at the bottom of thetrench. The trench 20 (typically only the top or ends) can be filledwith soil after placement of the reservoir 10 and associated piping 30as shown in FIG. 3 so that the trench reservoir 10 is encased in virgin,relatively compact soil or other ground materials thereat. The terms“full” and “filled” means that the reservoir has a normal operatingvolume but is not required to be at full volumetric capacity.

Typically, as shown in FIG. 3, the two primary surfaces 10 f, 10 r andthe bottom 10 b will be substantially flat, but expand sufficiently tosnugly abut compacted virgin earth formed by the trench. The ends 10 emay not have the natural support of the trench, depending on how thetrench is formed, so that the ends 10 e may take on an expandedoutwardly “bowed” shape during filling. Alternatively, the ends of thetrench can be filled to provide sufficient support prior to or duringthe “filling” of the reservoir 10.

FIG. 2C also illustrates that the geothermal ground loop 40 can includeat least one optional trickle line or conduit 80 that resides above thereservoir 10, typically adjacent or a distance above such as betweenabout 1 inch to about 1 foot above the reservoir, and is used to moistenan external surface of the reservoir 10 and/or soil thereabout tofacilitate heat conduction. The trickle line 80 can be configured as aconventional “soaker line” in greenhouses or other low flow type system.Where available, the at least one trickle line 80 can be connected to anon-potable or an untreated water source.

The reservoir 10 can comprise any suitable impermeable and/or waterproof material, typically having a wall thickness that does not undulynegatively impact heat transfer. The reservoir 10 can comprise apolymeric material having a wall thickness of between about 20 mils(0.002 inches) to about 100 mils (0.0100 inches), typically betweenabout 20 mils to about 60 mils. In some embodiments, the reservoir 10can comprise ethylene-propylene-diene monomer or terpolymer (EPDM)based, polyethylene, or other synthetic or natural rubber material suchas those materials used for pool or ground liners and the like. Thereservoir 10 can comprise a laminated material configuration ofdifferent layers of different materials or may comprise a unitarymonolithic material. In some embodiments, a foil or other heatconductive layer and/or coating may be used on an inner and/or outersurface to facilitate heat transfer.

In some embodiments, the reservoir 10 can comprise a material similar togeomembranes (also known as geomembrane liners) including thermoset,thermoplastic or thermoformable materials.

In one or more embodiments the reservoir may be TPO(thermoplastic-olefin) based. In yet other embodiments, the reservoir 10may be PVC (polyvinyl chloride) based. In still other embodiments, thereservoir 10 may be a polypropylene-based sheet formed into the desiredclosed shape. In these or other embodiments, the geomembrane may beflexible and capable of being rolled up for shipment. In certainembodiments, the reservoir 10 may include fiber reinforcement such asgeomembrane reinforcement materials that are well known to personshaving ordinary skill in the art.

Useful EPDM materials include those that are conventional andcommercially available. For example, EPDM geomembranes that may beappropriate for closed body reservoirs 10 are commercially availableunder the trade name “Pond Gard” from Firestone Specialty ProductsCompany, LLC (Carmel, Ind.). Also, EPDM geomembranes are disclosed innumerous United States patents including U.S. Pat. Nos. 3,280,082,4,732,925, 4,810,565, 5,162,436, 5,286,798, 5,370,755, 5,242,970,5,512,118, 2,260,111, 5,256,228, 5,582,890, 5,204,148, 5,389,715,5,854,327, 5,054,327, and 5,700,538, which are incorporated herein byreference for the purpose of teaching suitable water impermeablematerials. Useful TPO membranes are available under the trade name“Firestone TPO GEOMEMBRANE” (Firestone Specialty Products). Usefulflexible polypropylene sheets are available under the trade name“Firestone fPP-R GEOMEMBRANE” (Firestone Specialty Products).

The trench reservoir 10 may be flexible or semi-flexible and thin, so asto be unable to hold its closed operative shape without support outsidethe trench bed and may be rolled, folded or otherwise configured forshipment. The term “thin” means that the member is under about 0.010inches thick. Rigid or semi-rigid internal or external ribs and/or othersupport members may be used to facilitate installation as will bediscussed below.

The reservoir 10 can be configured to have a suitable burst strength orpressure suitable for the height of the unit 50 above the reservoir(FIG. 4), typically able to withstand about 1 pound of pressure forevery two feet. In some embodiments, the reservoir 10 can have a burststrength of about 15 psi or greater. In some embodiments, the burststrength is between about 15 psi to about 30 psi. However, reservoirs 10can have other burst strengths/pressures, particularly those used forhigh rise buildings which may have greater burst strengths.

The reservoir 10 can have one or more seams that allow a flat sheet orsheets of flexible material to form the enclosed reservoir body. Again,the seams can be configured to withstand a defined burst strength.

FIG. 4 illustrates the reservoir 10 positioned adjacent a single familyresidence with associated flow path (closed loop) pipes or conduits 30extending from unit 50 with a pump, e.g., a heat pump (e.g., a watersource heat pump) and/or a water-cooled condenser to at least onegeothermal reservoir 10 forming the geothermal ground loop 40. However,the reservoirs 10 may also be used for other geothermal ground loops,including residential and commercial or industrial applications such as,but not limited to, industrial buildings, office buildings,multi-dwelling residences, apartments, hotels, motels, and/or otherfacilities wishing to employ geothermal ground loops. The reservoirs 10may also be used with pipes, straight and/or coiled or pond or otherconventional geothermal ground loop heat transfer devices for a hybridsystem allowing for greater flexibility in land use and/or ground loopconfigurations.

The trench 20 typically resides a distance “D” (measured from an uppersurface, e.g., the top 10 t of the reservoir 10) that is between about2-10 feet below the ground surface, more typically between about 4-6feet sub-surface, but deeper or more shallow trenches may be appropriatein some uses.

The reservoir 10 can have a narrow substantially rectangular body 10body. The term “narrow” means that the reservoir is configured to have alength “L”, a width “W” and a height “H” such that H and L are muchlarger than W, typically at least about three times larger. Other closedshapes may be used with suitable geothermal heat transfer surface areas,typically so that the width is much less than the length and/or height.

The width can be between about 1 inch to about 12 inches but otherwidths may be used. Typically, the width is between about 3-9 inches,and more typically between about 4-6 inches, such as about 4 inches,about 5 inches and about 6 inches.

The height dimension can be between about 6 inches to about 6 feet,typically at least about 1 foot. The height can be about 2 feet, about2.5 feet, about 3 feet, about 3.5 feet, about 4 feet, about 4.5 feet,about 5 feet, about 5.5 feet or about 6 feet or any dimensiontherebetween (noting that a target 6 foot trench bed for the reservoir10 typically requires excavation of an 8-12 foot trench, for a suitablesubsurface depth).

In some embodiments, the length (L) is also greater than the height (H),typically at least 1.5 times greater, and more typically between about2-20 times greater than H, such as, for example, about 3-10 timesgreater. The length dimension can be between about 5 feet to about 100feet, typically between about 10 feet to about 100 feet, and moretypically between about 25 feet to about 50 feet. In other embodiments,shorter or longer lengths may be used.

The L×H dimensions can be configured to provide a sufficient heattransfer area on the front and back walls 10 f, 10 r for the volume ofliquid as the liquid flows from one end portion of the reservoir to theother, e.g., from an inlet to an outlet 11, 13 (which reverses forwinter and summer flow).

In some embodiments, the reservoir 10 can be oriented so that its lengthdimension is substantially vertical rather than its height H, but thiswill require a deeper trench 20.

In some particular embodiments, the reservoir 10 can be about 4 or 6inches wide, about 2 feet in height and about 25 feet long.

FIG. 5 illustrates an example of a summer or warm/hot weather flowarrangement of the reservoir 10 with the inlet port being the top port11 at the top of the reservoir 10. Because of the volume of thereservoir, the reservoir allows natural convection and/or conductivecooling of the hot liquid (water) that enters in the top so that coldwater exits the bottom. In addition, bottom flow in the bottom portionof the reservoir can improve cross circulation flow. FIG. 6A illustratesan example of a winter or cold weather flow arrangement with the inletbeing the bottom port 13.

FIGS. 6A-6C also illustrates an example of a substantially rigid supportmember 100 that can be arranged about an exterior portion of thereservoir 10 to help support the reservoir body 10 body. The supportmember 100 can have a length sufficient to extend above the trench hole;thus, it can have a length that is about 2-6 feet greater than theheight of the reservoir 10. The lower portion of the support member 100can include an aperture or slot 100 a that allows a length of conduit 30to extend therethrough. FIG. 6C illustrates a configuration of a supportmember 100 configured for attachment to the other end portion (not shownattached in FIG. 6A).

FIGS. 7A and 7B illustrate examples of alternate support members 100′,100″. FIG. 7A shows the use of a plurality of aligned rings 101 thatcouple to an upstanding support rod or beam 103. FIG. 7B shows the useof external ribs 104 that may optionally couple to handles 105 for easeof installation. Although not shown, internal ribs or rigid orsemi-rigid support members may also or alternately be used.

FIGS. 7C and 7D illustrate that the ends 10 e of the reservoir 10 caninclude external long (typically fabric) loop channels 102 that snuglyreceive support members 103 (e.g., rods or bars). The loop channels 102and support members 103 can cooperate to provide support to ends of thereservoirs 10 where the trench may be less straight potentially allowingfor more expansion or “bowing” outward of the reservoir 10. Althoughshown as two sets of loop channels 102 on outer edges of the ends 10 e,one or more than two sets may be used. Other external features thatfacilitate handling may also be used such as straps, handles and thelike. These features may be integrated or releasably attached to thereservoir (or cover 110, FIG. 13, where used).

In some particular embodiments, a respective reservoir 10 can beconfigured to hold at least about 100 gallons of circulating liquidassociated with the ground loop 40. The reservoir 10 can have a lengthof about 25 feet, a width of about 4-6 inches, and a height of about 2feet. For example, the reservoir 10 can hold about 124 gallons for a 25foot long×2 foot high×4 inch wide reservoir. A typical residentialsingle family home may use a reservoir or reservoirs that have about200-400 gallons capacity (for about a 2 ton heat system).

It is contemplated that a length of about 25 feet of reservoir(s) 10will be equivalent to a 400-500 foot per ton of looped ¾ inch pipe. Thereservoir 10 can have over 325 times the volume of water based on a 6inch trench and about 217 times the water based on a 4 inch trench.Because the reservoir 10 substantially fills a respective trench 20,post-placement, during installation, the surface contact area per onefoot of trench for a reservoir 10 can be many times greater than thelooped pipe systems making the installation easy and practical (over 35times greater for a 6 inch trench or 30 times greater for a 4 inchtrench). The trench area or volume needed is reduced for the same BTUtransfer, greatly reducing the installation cost over coiled pipe ordeep bore systems.

Stated differently, the volume of water in a typical one ton system with¾ inch pipe is about 400-500 foot of trench of a one-pipe system. Basedon a 400 foot system, the volume of water is about 9.18 gallons. Theentire heat exchange is less than about 3.1 minutes which is relativelyshort. On an equivalent one-tone flexible or semi-flexible reservoirusing a 25 foot long trench-reservoir (4 inches wide), the volume ofwater is about 124.7 gallons and the entire water is exchanged in about41.5 minutes. This is a much longer time for heat exchange and also ismore efficient due to the greater heat exchange surface area of thereservoir 10. The surface area of the ¾ inch pipe is about 78.5 squarefeet while the reservoir is 118 square feet (about 1.5 times greater),while requiring only 1/16 of the trench system length.

In some embodiments, the reservoir 10 has substantially laminar liquid(water) flow. The geothermal loop 40 can be configured so that thereservoir 10 can have substantially an entire water exchange in about30-90 minutes, typically about 35-45 minutes, from a time into one port11 to exit from the other 13, so that liquid enters on a bottom portionadjacent or at one end and exits at a top portion adjacent or at theother end, and vice versa, depending on heating or cooling heat exchange(whether for winter or summer uses).

The liquid (inlet and outlet) ports 11, 13 can reside on opposing endportions of the reservoir 10, typically on an upper end portion at oneend portion and a lower end portion at the other. The ports 11, 13 canreside on the top 10 t and bottom 10 b of the reservoir 10. In otherembodiments, the ports 11, 13 can reside on an upper or lower portion ofthe front and/or rear sides 10 f, 10 r. The ports 11, 13 can comprisestandardized pipe connectors or fittings 11 c, 13 c that connect to theflow path pipes 30. The fittings 11 c, 13 c can be installed at a fieldsite or at an OEM (original equipment manufacturing) facility. Thefittings 11 c, 13 c can be ¾ inch pipe fittings and the flow path pipes30 can also be ¾ inch pipes or conduit. Other size fittings and pipes 30may also be employed, typically between about 0.5 inches to about 1 inchin diameter, but smaller or larger sizes may be appropriate for someuses.

As shown, for example, in FIG. 5, the ports 11, 13 can be configuredwith a pipe or conduit segment 16 that resides a distance inside thereservoir and can include with nozzles, diffusers, or elbows 17 and/orother components that facilitate cross flow at entry into the reservoirto promote heat transfer. FIG. 5 illustrates an external elbow 17 andFIG. 2C illustrates an internal elbow 17.

Although shown as a single inlet and a single exit port 11, 13, multipleinlet and/or exit ports may be used. The pipes or conduits from themultiple ports can combine in a “Y” interface pipe upstream ordownstream (depending on flow direction) of the reservoir 10. Wheremultiple inlet or exit ports 11, 13 are used, one set can be configuredabout one end portion or at other positions along the body 10 b and theother set about the other opposing (long) end portion or at otherpositions along the body 10 b to promote through flow to move up anddown over a length of the reservoir for increasing heat transfer.

As shown in FIGS. 8, 9A and 9B, in some embodiments, a geothermal loop40 can include a plurality of reservoirs 10 ₁, 10 ₂, typically with onereservoir 10 ₁, 10 ₂ feeding the next. As indicated by the arrows forflow direction, FIG. 8 illustrates a cold weather arrangement where flowis in the first reservoir 101 at the bottom port 11, flows through thefirst reservoir, exits the top port 13 and flow then enters the secondreservoir at the bottom port 11 and exits at the top port 13. The flowdirection is reversed for summer or warm weather operation. When morethan one reservoir 10 is used for a particular site or a particulargeothermal loop 40, different sized and/or configured reservoirs 10 maybe used.

FIGS. 9A and 9B illustrate a four reservoir 10 ₁-10 ₄ configuration fora geothermal ground loop 40. FIG. 9A is an end view and FIG. 9B is a topview of the four reservoir connection. The flow direction is shown bythe arrows from flow in 30 i to flow out 30 o, as into the bottom port13, out the top port 11, then into the next adjacent reservoir 10 ₂bottom port 13, out of the top port 11, and so forth for winter or coldweather flow. The reverse is true warm weather flow, e.g., in the topport 11 of reservoir 10 ₄, and out the bottom port 13. As shown in FIG.9B, the top and bottom ports 11, 13 of adjacent pairs of the reservoirs,e.g., 10 ₁,10 ₂ and 10 ₂, 10 ₃ can be aligned to be on the same end ofthe reservoir body. This may be accomplished by using one reservoir 10 ₂in an upside down orientation from another adjacent one, e.g., 10 ₁ and10 ₂. However, other configurations may be used.

In some embodiments, the reservoirs 10 can be configured as modular sizereservoirs for ease in scaling for installations requiring differenttonnage heating/cooling. Thus, each 25 foot section can be rated for adefined length per ton of heat transfer capacity (for a 2 inch or a fourinch trench).

It is contemplated that a 2400 square foot residence, typically using afour ton heat system may use about 100 feet of reservoir 10 (which maybe provided as four 25 foot long reservoirs 10).

FIGS. 10A and 10B illustrate that the reservoir 10 can include at leastone, shown as a plurality, of internal partitions 200. The partitions200 can alternate to extend down 201 or up 202 to define flow spaces 203to direct flow through the reservoir 10 to travel up and down to forcemore exposure of the liquid to the primary heat transfer walls 10 r, 10f. The partitions may be rigid or flexible. The partitions 200 may beattached so as to remain substantially vertical or may be hinged toallow flow to move them in a flow direction.

To change the flow direction, a user can manually change the inlet andoutlet flow conduits at the circulation pump which is typically on anexterior location of the building to change flow direction through theground loop 40 and at least one reservoir 10 for winter or summerdirections.

Valve(s), such as a reversible valve, can be used for automated flowcontrol and (external, ambient) temperature sensors (e.g.,thermocouples) may be used to automatically dictate flow direction. Aprocessor or electronic controller can be in communication with thesensor(s) to automatically direct the valve operation and flowdirection. The controller or processor can monitor temperature andchange flow direction when it remains above a defined threshold for adefined time before flow direction is changed.

In some embodiments, temperature sensors may be provided to senseTemperature in and Temperature out of one or more reservoirs and pumprates can be adjusted accordingly.

FIGS. 11A, 11B and 12A-12C illustrate additional embodiments of areservoir 10. In these embodiments, the reservoir 10 can reside insidean external cover 110. As shown in FIG. 13, the cover 110 can have ashape and size that substantially corresponds to that of the reservoir10. The cover 110 can totally or partially enclose the reservoir 10 toprotect the reservoir 10 from rocks and other objects that might damageor puncture the reservoir 10.

The external cover 110 can comprise a thin flexible material having athickness that is typically between about 10 mil to about 100 mil, suchas between about 20 to 50 mil, including about 20 mil, about 25 mil,about 30 mil, about 40 mil, about 45 mil and about 50 mil. The materialcan be permeable, semi-permeable or impermeable to water.

The external cover 110 can be a different material than the reservoir10. The cover 110 may have a denser material than the reservoir 10. Thecover 110 and the reservoir 10 can each be formed of a material thatprovides a suitable thermal conductance to provide suitable geothermalheat exchange. One or more of each can have a coating or multi-layeredmaterial forming internal and/or external surfaces on the walls thereofto promote thermal conductance. Examples of suitable coatings ormaterials include, but are not limited to, non-reactive metals (at leastwhere used as an internal layer or coating) such as aluminum foil,cellulose or paper based materials with glass fibers and other fillers,and other suitable material.

The external cover 110 can be reinforced with fibers, ribs, materials orother reinforcement or strengthening members or materials. The externalcover 110 may be biodegradeable over time.

As shown in FIGS. 12A-12C, the reservoir 10 can reside inside theexternal cover 110 and may be held loose therein prior to filling. Thecover 110 can expand to conform to a trench as the reservoir 10 isfilled with water. The cover 110 and the reservoir 10 can be conformableto water pressure so as to expand outwardly in response to filling.

As shown in FIG. 12A, the reservoir 10 expands during filling whileinside the cover 110. As the reservoir 10 expands, it pushes outwardagainst the cover 110 thereby expanding the cover 110 (FIG. 12C) causingboth the cover 110 and reservoir 10 to conform to and abut a trenchwall.

In other embodiments, the cover 110 can be attached over at least amajor portion of a surface area of the reservoir, e.g., laminated to thereservoir 10 so that each is concurrently responsive to expand outwardin response to filling with water.

The reservoir 10 can be attached to the cover 110 at one or morelocations via adhesive, VELCRO, sewn attachments, or other attachmentconfigurations. The cover 110 and the reservoir 10 can each be held viaone or more collars about one or both ports 11, 13. The cover 110 caninclude apertures, slots, ports or open regions 111 (FIG. 13) that allowthe plumbing connections to the reservoir 10.

The external components and features described above (e.g., FIGS. 7A-7D)with respect to the reservoir 10 can be provided on the cover 110 tofacilitate handling and installation. FIG. 13 illustrates the use of atleast one top strap on the cover 110. However, other externallyaccessible features or members can be used.

FIG. 11A shows that the cover 110 may be configured to expose the endwalls 10 e of the reservoir 10 and each may include handling features,such as loops 101 that can attach to a rod 103. FIG. 11B shows that thecover 110 can substantially encase the reservoir 10.

As shown in FIG. 14, in some embodiments, water, gas or other fluid maybe introduced into an interior cavity 125 formed between the cover 110and reservoir 10 to promote thermal conductivity. The wall(s) of theflexible cover can expand outward as the reservoir is filled and/or asthe interior cavity is filled as the interior cavity 125 resides betweenthe outer wall of the reservoir and the inner wall of the cover. Thecavity 125 may be configured to circulate or discharge fluid or holdfluid captured, once filled. If the fluid leaches from the interiorcavity 125, a refill port 126 with and associated plumbing 125 p may beused to re-fill the cavity 125 (manually or automatically). Forautomated configurations, one or more pressure sensors 128 in the cavity125 can be externally monitored and used to facilitate the refill atsuitable times and amounts.

As shown in FIGS. 15-17, a jig 300 can be used to lower the reservoir 10into the (pre-formed/prepared) trench 20. The jig 300 can be configuredto hold the reservoir 10 at a plurality of spaced apart upper attachmentzones 312, typically at zones, regions or points that are (symmetricallyor asymmetrically) spaced apart from each other a distance “d1” whichcan be about 1-3 feet, typically about 2 feet (24″), apart. Theattachment zones 312 can be along a perimeter and/or along a center linebetween the two long sides of the frame via cross members 301 thatattach to the upper rigid rectangular frame 305. So, for example, thejig 300 can be attached to about 12 points on a 25 ft long reservoir orcell 10. The top of the jig 300 t can have an open center gap spaces 302between cross structures or cross members 301.

In some embodiments, the jig 300 is provided in two releasablyattachable segments with the cross-member 310 providing the interfacetherebetween.

The enlarged view of the detail of FIG. 15 illustrates an exemplaryattachment zone 305 p using the cross-member 301 showing that one ormore carriage bolts 305 b can be used to allow the jig to be transportedin two or more sections due to the length of the jig. The carriagebolt(s) 305 b can be used due to smooth inside of the jig's sides 315.The carriage bolt has the smooth top that can rest on the side of thecell for installation. In other embodiments, the jig 300 can be providedas a single piece unit (relatively long, e.g., about 25 feet) that maybe challenging for use with small equipment. In the embodiment show, thejig 300 is a two piece system, but the jig 300 can also be provided asthree or more cooperating pieces that can be assembled onsite orotherwise.

As shown in FIGS. 16 and 17, the upper frame 305 can hold downwardlysidewalls 315 that have sufficient rigidity to maintain their shape andthat have increased rigidity over the unfilled reservoir 10 (andexternal liner 110, where used).

The sidewalls 315 can be on all four sides or on a subset of the sidesof the frame 305 and each can extend down the same or different lengths.As shown, the sidewalls 315 define a rectangular enclosure 315 e thatencloses a reservoir top 10 t. The sidewalls 315 can extend down on allfour sides, all of the way around the upper perimeter frame 305, todefine the enclosure space 315 e. The sidewalls 315 can extend down adistance “H” that is between about 1-3 feet, typically about 18 inches.The sidewalls 315 can be formed of sheet metal that attaches to angleiron or formed rigid metal bars of the frame 305. For example, 18 to 10gauge sheet metal can be used for the sidewalls 315.

As shown in FIG. 17, the reservoir 10 can be suspended to hang below thejig 300 and only an upper portion (e.g., 1-2 feet, such as about 18″) ofthe reservoir 10 is inside the enclosure of the jig's sheet metal 315.The jig 300 can have a length corresponding to the length of thereservoir 10 being installed.

FIG. 15 is a side view of the jig 300 without the reservoir 10 orsidewalls 315 attached. FIG. 15 shows that ropes, chords, wires, cablesor other support members 310 ₁, 310 ₂ can be attached to each endportion of the frame 305 and, when attached to a center lift point 320at inner adjacent end portion of the members 310 ₁, 310 ₂, define an Aframe. A lift bolt 320 b or other attachment means can attach to thelift point to hoist the assembly into the trench 20 (FIG. 17). The jig300 can be lifted from the center point 320 of the A frame. However, itis contemplated that the jig can be lifted via both ends or at otherlocations and the A frame is not required.

FIG. 16 shows the end of the jig and the attachment of the end 310 a ofthe A frame. This figure also shows the width of the jig 300 is thetrench width (such as, for example, about 6″). The jig 300 holds thereservoir 10 at spaced apart points 305 p (e.g., about every 2 feet)along the top of the cell. The jig hooks 306 that hold the reservoir 10are shown in FIG. 16.

FIG. 17 is an end view of the cell lowered in the trench and holding thecell. At this position, the cell is filled with water. After beingfilled with water, the earth in the trench 20 is refilled around the topof the jig 300 via spaces 302 to allow good conformation of thereservoir at the top.

In digging the trench, the top of the trench 20 can be wide and mayallow the reservoir 10 to balloon at the top. In order to inhibit orstop this response, the earth can be filled in to the top of the jig300. Once the cell or reservoir 10 is filled with liquid and the earthhas been filled around the jig 300, the hooks 306 can be released fromthe jig 300 and the jig 300 can be removed from the trench (or it mayremain in position or in the trench above the reservoir).

In some embodiments, the jig 300 can also be configured to hold a liner110 if installed with the reservoir 10, such as using liner attachmentmembers 312 shown in FIG. 16.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. In the claims, means-plus-function clauses, if used, areintended to cover the structures described herein as performing therecited function and not only structural equivalents but also equivalentstructures. Therefore, it is to be understood that the foregoing isillustrative of the present invention and is not to be construed aslimited to the specific embodiments disclosed, and that modifications tothe disclosed embodiments, as well as other embodiments, are intended tobe included within the scope of the appended claims. The invention isdefined by the following claims, with equivalents of the claims to beincluded therein.

1. A geothermal heat exchanger for a ground trench, comprising: asubstantially rectangular reservoir body having external flexible wallsand is configured to selectively heat or cool liquid therein, dependingon flow direction therethrough, the reservoir body having width, height,and length dimensions, wherein the width dimension is in a range ofabout 1 inch to about 12 inches and the length dimension is in a rangeof about 10 feet to about 100 feet, wherein the reservoir body has afirst port that is longitudinally spaced apart in the length dimensionfrom a second port, and wherein the reservoir body is sufficientlyflexible to be rolled and/or folded for shipment; and a length of pipeor conduit that extends a distance inward into the reservoir body fromone or both of the first and second ports, with an inner facing endsized and configured to be under liquid level during operation tofacilitate cross flow.
 2. The geothermal heat exchanger of claim 1,wherein the pipe or conduit extends straight down inside the reservoirbody.
 3. The geothermal heat exchanger of claim 1, wherein the pipe orconduit comprise fittings that engage an external length of pipe orconduit in a geothermal loop that extends into a residence or building,wherein the geothermal heat exchanger is adapted to be in fluidcommunication with a heat pump or water-cooled condenser to providewater to the geothermal loop, and wherein, in operation, the heat pumpor water-cooled condenser is remote from the reservoir body.
 4. Thegeothermal heat exchanger of claim 1, wherein the width dimension isbetween about 4-6 inches, and wherein the length dimension is at leasttwo times greater than the height dimension.
 5. The geothermal heatexchanger of claim 1, wherein the reservoir body has front and rearprimary walls configured as opposing long sides of the reservoir bodyconnected with first and second end walls configured as opposing shortsides that are orthogonal to the front and rear primary walls, the shortsides extending along the width dimension, the long sides extendingalong the length dimension, wherein the short sides and long sides havea height as the height dimension that is greater than the width of theshort sides.
 6. The geothermal heat exchanger of claim 1, furthercomprising a first pipe connector and a second pipe connector sealablyattached to the reservoir body, wherein the first pipe connector iscoupled to the first port and the second pipe connector is coupled tothe second port.
 7. The geothermal heat exchanger of claim 6, wherein atleast one of the first pipe connector or the second pipe connector isattached to a ceiling of the reservoir body.
 8. The geothermal heatexchanger of claim 5, wherein the reservoir body has a ceiling and afloor that join the first and second end walls and the opposing longsides of the reservoir body, and wherein the first and second end walls,the ceiling and the floor have a planar configuration when the reservoirbody is at full liquid volumetric capacity.
 9. The geothermal heatexchanger of claim 1, wherein the reservoir body has a volumetriccapacity in a range of 200-400 gallons, wherein when filled to a maximumvolumetric capacity, the reservoir body has a rectangular shape withprimary front and rear walls being substantially planar, and wherein thewidth, height and length dimensions of material forming the reservoirbody are unchanged from an empty state.
 10. The geothermal heatexchanger of claim 5, wherein the reservoir body has a ceiling and afloor, wherein the ceiling joins the left and right end walls and thefront and rear primary walls using first, second, third and fourthseams, wherein the floor joins the left and right end walls and thefront and rear primary walls using first, second, third and fourthseams, and wherein the first, second, third and fourth seams of theceiling and floor are parallel when the reservoir body is at fullvolumetric capacity.
 11. The geothermal heat exchanger of claim 1,wherein the reservoir body has a volumetric capacity in a range of200-400 gallons, and wherein, when filled to maximum volumetriccapacity, a ceiling and floor of the reservoir body are planar.
 12. Thegeothermal heat exchanger of claim 1, wherein the length of pipe orconduit is parallel to and adjacent at least one of the short sides. 13.The geothermal heat exchanger of claim 5, wherein the short sides andlong sides of the reservoir body are four spaced apart external flexibleside walls bounding a rectangular chamber, and wherein the reservoirbody is configured to expand from a pre-installation shape to aliquid-filled post-installation shape and retain the filled shape duringoperation over successive closed loop water flow heat exchange cycles.14. The geothermal heat exchanger of claim 1, wherein the reservoir bodyhas a liquid-filled post installation shape that is substantiallyrectangular, and wherein the length dimension is in a range of betweenabout 2-20 times greater than the height dimension.
 15. The geothermalheat exchanger of claim 5, wherein the reservoir body is substantiallyrectangular, and wherein the front and rear primary walls are formed ofa thin, water-impermeable material.
 16. A method of installing ageothermal heat transfer system, comprising: placing a first geothermalheat exchange reservoir with at least one inlet port and at least onespaced apart outlet port in a horizontal ground trench having a floorand upwardly extending trench walls; placing a second geothermal heatexchange reservoir with at least one spaced apart outlet port in thehorizontal ground trench with the first geothermal heat exchangereservoir or in a different horizontal ground trench having a floor andupwardly extending trench walls; providing a closed loop flow path thatconnects the first and second geothermal heat exchange reservoirs to aheat pump or water cooled condenser; and flowing liquid into the firstand second geothermal heat exchange reservoirs causing at least someexternal walls of each of the first and second geothermal heat exchangereservoirs to expand outward to contact and conform to the trench walls.17. The method of claim 16, wherein the first and second geothermal heatexchange reservoirs are substantially rectangular and have a length thatis between about 10-100 feet and a width between about 2-4 inches, andwherein the placing of the first geothermal heat exchange reservoir andthe placing of the second geothermal heat exchange reservoir are carriedout to position a respective top surface of the first and secondgeothermal heat exchange reservoirs at between 4-6 feet sub-surface. 18.The method of claim 16, wherein the first and second geothermal heatexchange reservoirs comprise flexible external longitudinally extendingfront and rear walls and a bottom, wherein the horizontal groundtrenches are compacted, virgin-earth horizontal ground trenches, andwherein the flowing liquid causes the bottom and the front and rearwalls to expand outward to conform to the compacted, virgin-earth of arespective trench bottom and upwardly extending trench walls tofacilitate heat transfer.
 19. The method of claim 16, wherein the firstand second geothermal heat exchange reservoirs each comprise first andsecond fluid ports that are longitudinally spaced apart, and whereinflow in the closed loop flow path is in a first direction in coldweather and in an opposing second direction in warm weather such that(i) for winter and/or cold weather, water flows in the closed loop flowpath into the first reservoir then into the second reservoir and (ii)for summer and/or warm weather, water flows in the closed loop flow pathinto the second reservoir then into the first reservoir.
 20. A method ofgeothermal heat transfer, comprising: flowing water from a pumpassociated with a heat exchanger or water-cooled condenser in ageothermal flow path in a first direction during summer and in anopposing direction during winter, wherein the geothermal flow pathcomprises at least one geothermal reservoir, wherein the at least onegeothermal reservoir has a height dimension, a width dimension that isbetween about 1-12 inches, and a length dimension that is between about10-100 feet, wherein the height dimension is greater than the widthdimension and the length dimension is greater than the height dimension,wherein the at least one geothermal reservoir comprises opposing firstand second long walls defining the length dimension, wherein the atleast one geothermal reservoir resides in a horizontal compacted soiltrench a distance below ground surface with the first and second longwalls snugly contacting and conforming to a trench wall shape thereat,wherein, pre-installation, the at least one geothermal reservoir issufficiently flexible to be rolled or folded.
 21. The method of claim20, wherein the at least one geothermal reservoir comprises a first portand a second port spaced apart in the length dimension, each of thefirst and second ports comprising connectors sealably attached theretoand coupled to conduit that extends between respective pairs of the atleast one geothermal reservoir to form part of the geothermal flow path,wherein the at least one geothermal reservoir has a bottom and a ceilingwith the opposing first and second long walls attached thereto and withopposing first and second short end walls defining the width dimensionattached thereto, and wherein the flowing water through the at least onegeothermal heat exchange reservoir is carried out so that the at leastone geothermal reservoir has substantially laminar water flow and sothat water in a respective at least one geothermal reservoir isexchanged in between 30-90 minutes.